It's hard to believe that Bermuda wasn't always a vacation paradise, but since the island lies about 600 nautical miles from the U.S. East Coast, it was once a strategic military outpost for Great Britain. During the American Revolution and the War of 1812, its proximity to the young American nation made it an ideal spot for Britain to station troops and deploy arms. Once nicknamed the Gibraltar of the West, Bermuda was the Royal Navy’s Western Atlantic headquarters for many years.

During the American Civil War, the Confederacy relied on Bermuda as a checkpoint for British ships, allowing them to evade the Union blockade and deliver goods to the South. The island also served as an important naval base during both world wars. It’s no surprise, then, that Bermuda still houses several historic forts. Here are five strongholds worth a visit.

1 Fort Hamilton, Pembroke Parish

Fort Hamilton

Construction of this famous fort began in 1868 by order of the Duke of Wellington. Originally intended to protect Hamilton Harbour from an American invasion, the fort was already considered outdated before its completion in the 1870s. Outfitted with a moat, underground passageways and 18-ton guns, Fort Hamilton has since been transformed into a park filled with gardens.

2 Fort St. Catherine, St. George's Parish

Fort St. Catherine

The largest and most visually spectacular fort in Bermuda, Fort St. Catherine towers above pink-sand beaches on a finger of land snaking out into the sea. Constructed in 1614, the fort underwent numerous upgrades in the 19th century. Today, its interior serves as a museum of Bermudian history. You can explore the fort’s massive ramparts, antique artillery, labyrinthine tunnels and chambers carved deep into the bedrock, plus soak up incredible views of Achilles Bay.

3 Martello Tower, Ferry Reach, St. George's Parish

Martello Tower

With walls as thick as 11 feet, Martello Tower was built by the British to withstand potential cannon fire from French or American forces. Restored in 2008, Martello looks much as it did when it was constructed in the 1820s. It’s also Bermuda’s only egg-shaped fort, closely resembling designs commonly found along the English coastline.

4 Royal Naval Dockyard, Sandys Parish

Royal Naval Dockyard

Although visitors to Bermuda may think of the Royal Naval Dockyard as a centre of arts, crafts, dining and shopping, the complex was initially constructed by the British Army’s Royal Engineers in the 1860s to protect against an American invasion. Visit The Keep, which now houses the National Museum of Bermuda. It was built to guard the entire naval base against attack, whether by land or sea, and features seven irregular bastions and ramparts. And don’t miss the painstakingly restored Commissioner’s House, which was erected for the civilian commissioner in charge of the Dockyard. It will also be home to the 35th America's Cup Event Village in 2017.

5 Great Head Battery and Park, St. George's Parish

Great Head Battery and Park

Located at Bermuda’s easternmost point, the Great Head Battery on St. David’s Island offers stunning views of the sea and St. George’s. Completed in 1910, the fort was designed to defend the Narrows Channel. Coastal defense guns lined the fort, although none were ever fired in combat. Today, the area is a 24-acre park that serves as a memorial to Bermudian troops.